—What do the letters “DOS” ______？
—Disk Operating System.
| A．call for | B．stand for | C．head for | D．care for |
Nearly all the streets are in straight lines, ________ from east to west. Those ________ run from north to south are called avenues.
| A．running; that | B．run; who | C．running; who | D．run; that |
In warm weather fruit and meat ________ long.
| A．don’t keep | B．can’t be kept |
| C．are not kept | D．aren’t keeping |
―Was the doctor there when you arrived?
―Yes, but he ______ out a moment later.
| A．had gone | B．has gone | C．went | D．is going |
―________ for Beijing?
―Yes. And I’ll come back in three months.
| A．Have you left | B．Are you leaving |
| C．Do you leave | D．Did you leave |
―What were you doing when I called you yesterday afternoon?
―I ________ my homework and I was starting to take a bath.
| A．had just finished | B．was finished |
| C．have already finished | D．was going to finish |